The device of this instrument is a writing instrument. Throughout the disclosure, reference will be made to various types of writing instruments and in particular ball point pens, which is preferred for use with this invention. It will be seen that any type of writing or marking instrument may be used in my invention, including mechanical pens, such as ball point, felt marking, hard tipped marking, metal fountain and other types, mechanical pencils, standard pencils, and all other types of marking instruments.
While the exact type of writing instrument is not critical to this invention, it will be seen that the advantage of having the means to write in the same instrument that provides conversion tables or other reference material will have a great advantage to the user.
In the country of the United States there has been a long standing usage of the English system of measurements. Recently, decision has been made to convert to the metric system to bring the country's usage more in alignment with that of the rest of the world. Unfortunately, most of the residents of the United States have been taught only the English system and have used it throughout their lives. Learning the metric system and, in particular, the problem of converting English measurement over to the metric equivelant is very difficult and places quite a burden on the residents of the United States.
It is, thus, most desirable that the person be able to readily convert between English and metric systems as the person is handling other duties. For example, the increasing use of metric weights and measures requires that the person be ready to convert the measurements in order to comparison shop. It is usually necessary to use a writing instrument for such comparison and this inventor has realized the advantage of combining the two needs in one instrument.
While the use of metric conversion is an immediate need, it will be apparent to the reader that conversion tables of all types will be useful and can be applied in my invention. In addition, the selective presentation of a variety of types of data including multiplication tables and the like can easily be inserted in my invention and used to the great advantage of the user.
It is therefore, an object of this invention, to provide a writing instrument which will selectively display written indicia to the viewer without causing the writer to refer to any other source material.
It is an additional object of this invention to provide a writing instrument which will combine the selection of the indicia with the working mechanism of the mechanical writing instrument and that through that commonality, offer the advantage of compactness, simplicity and reduced cost.
It is an additional object of this invention to provide a writing instrument which will selectively display, under the user's control, a series of conversion formulas which will allow the user to convert from one weight measure system to another.